menon 2/22/06 10:05 AM Page 20 Biomimetics – A new approach for space system design menon 2/22/06 10:05 AM Page 21 Biomimetics Carlo Menon, Mark Ayre Advanced Concepts Team, ESA Directorate of European Union and Industrial Programmes, ESTEC, Noordwijk, The Netherlands Alex Ellery Surrey Space Centre, University of Surrey, United Kingdom iological systems represent millions of years of trial-and-error learning through natural selection according to the most stringent of metrics: survival. ‘Biomimetics’ may be defined as the practice of ‘reverse engineering’ ideas and concepts from nature and implementing them in a field Bof technology. This reverse engineering has recently attracted significant research due to an increasing realisation that many of the problems faced by engineers are similar to those already solved by nature. ESA’s Advanced Concepts Team views biomimetics as a means of finding new and realistic technologies for application in future space missions. The research is not concerned with mere imitation of biological systems, but rather focuses on understanding the fundamental processes and mechanisms used in nature, in order to discover promising concepts valuable to space engineering. Benefits are expected in areas as diverse as sensors, actuators, smart materials, locomotion, and autonomous operations. Biomimetics Technology Tree Biomimetics The success of biological organisms in Novel Structures solving problems encountered in their Structures Dynamic/adaptive Structures environments is attributed to the process of Structures and Deployment, Folding and Packing natural selection, whose primary metric is Materials survival – failure implies extinction! Such Composites biological solutions offer insights into Materials Bio-Incorporated Composites alternative strategies for designing Smart Materials engineering systems. Biological systems Muscles and Actuators represent millions of years (billions of years Mechanisms in the case of microbes) of trial-and-error Locomotion learning through natural selection. Nature Mechanisms and has implemented 550 million years of Processes Novel Processes multi-cellular evolution, generating some Processes Thermal Management 5-10 million species, of which only some Fabrication Power Generation and Storage 1.7 million have so far been catalogued. This represents a huge database of Classical Artificial Intelligence biologically-inspired solutions to problems. Behavioural Artificial Intelligence There is thus much that engineers can learn Behaviour Behaviour and Learning Mechanisms from biology and emulate in their design of Control Swarm Intelligence (DAI) engineering systems – this discipline is called ‘biomimetics’. Reflexive Control Control Biomimetics involves ‘reverse engin- Rhythmic Control eering’ the principles of evolutionary design of biological organisms in order to Vision implement biological solutions to general Sensors Hearing engineering problems. The problems Sensors and Touch encountered by biological systems are Communication Taste and Smell similar in many respects to those encountered in engineered systems. It Communication Passive Group Communication seems appropriate therefore to examine biological solutions in order to analyse Ecological Mechanisms Genetic Mechanisms engineering issues. Research efforts in this Generational Generational direction have recently become significant Biomimicry Cultural Mechanisms Geneering/Human Alteration in interdisciplinary-engineering topics. www.esa.int esa bulletin 125 - february 2006 21 menon 2/22/06 10:05 AM Page 22 Industrial Programmes Biomimetics Applied to Space Engineering of onboard autonomy. Although autonomy Implementing Concepts from Nature in A spacecraft is designed to cope with a is typically associated with exploration Technological Fields hostile and highly variable physical spacecraft, the issue of autonomy is Reverse engineering of ideas and concepts environment. Although it may not seem also relevant to Earth-orbiting platforms, from nature and implementing them in a totally appropriate to examine biological as ground-station-based control is the particular technological field is not a organisms that have evolved in the dominant factor in operational costs. straightforward process. There are a terrestrial environment in order to seek Biological organisms evolve, adapt number of major differences between novel solutions to problems encountered in and learn in highly variable environ- engineered products and biological space engineering, we seek not to replicate ments whilst maintaining their systems when designing a bio-inspired biological organisms in toto, but rather to functionality. They exhibit autonomy par system:* abstract the biological principles by which excellence, and could therefore inspire organisms function and survive. The new solutions for highly autonomous 1. Most organisms are characterised by appropriate level of abstraction of such engineered systems. cylindrical shapes and curved bio-inspiration is not a trivial issue. A surfaces, while engineered structures successful example of already developed Miniaturisation generally have straight edges and bio-inspired engineered solutions is Volume, mass and power are important and sharp corners. represented by artificial neural networks often critical parameters for spacecraft and 2. Engineered products are generally used for control systems, which are highly their payloads. Their reduction implies constructed from homogeneous simplified and re-structured abstractions several benefits, including significant cost materials, while biological materials of biological neural architectures. savings. are composites to a variety of degrees. Biomimetics applied to space 3. Engineered structures are designed for Satisfying solutions engineering promises the prospect of stiffness (and so tend to be brittle), Engineers often seek optimal solutions in greater miniaturisation, integration and while organisms favour strength over spacecraft and payload design. The process, packaging efficiency, which biological stiffness for toughness. which is generally very costly/time systems exhibit. This has natural synergies 4. Biological features often have multi- consuming, could benefit if ‘satisfying with micro-systems technology, which functional roles. solutions’ are already known. Satisfying integrates electronics, mechanics and solutions represent the approach in biology optics on a highly reduced scale to achieve When reverse-engineering concepts whereby the historical constraints of high performance and high complexity from nature and adopting biomimetic available genetic resources lead to the within a very small volume (e.g. a few solutions, the following general caveats are evolution of organisms compliant with the mm3). An important consideration for such proposed in order to obtain applicable prevailing environment. miniaturised systems is that their surface- engineering solutions:** area/volume ratio increases, and this has (i) Biomimetics may be a good starting Robustness and adaptability two important consequences: their power point. Robustness and adaptability are dissipation increases, requiring greater (ii) Pure biomimetic approaches can particularly critical issues in space, as the power volume density, and their structural yield non-optimal performance environments to be explored are typically strength increases, allowing greater solutions. unknown and vary with unpredictable loadings. (iii) Sometimes optimal solutions result dynamics. The most sophisticated from traditional technology. engineered systems are often lacking in System design (iv) Biology relies heavily on good robustness and adaptability, while simple A characteristic of natural systems is their integration through the use of natural organisms excel in terms of holistic design. A more systematic multifunctional structures. adaptability to their environment, adoption of biomimetics in space systems actuation flexibility and sensory design could involve a new approach that A wide number of engineering disciplines robustness. Ideas inspired by nature could treats a functional unit in a concurrent and could be analysed taking into account therefore represent valuable solutions with multidisciplinary way. The payload of the existing solutions adopted by nature, some regard to these issues. spacecraft is thereby not treated separately, of which are shown in the ‘Biomimetics but as an integrated, indeed primary output Technology Tree’ on the facing page. Autonomy of the space mission – its behaviour. The Although this tree could be greatly Another critical issue for space systems is environment also acts as a feedback that of autonomy – the distances involved, mechanism to the spacecraft. This provides particularly once spacecraft venture the basis for the modular and hierarchical * From P. Husbands et al. (1998), Connection Science, pp. 185-210. beyond Earth orbit, preclude real-time division of the spacecraft. ** From R. Michelson & M. Navqi (2003), Von Karman Institute for Fluid control, thus necessitating high degrees Dynamics Lecture Series. 22 esa bulletin 125 - february 2006 www.esa.int menon 2/22/06 10:05 AM Page 23 Biomimetics expanded and extended, it can be used as a starting point for future studies and analyses. Research on Biomimetics Considering the advantages of reverse- engineering concepts from nature and taking into account the major differences between engineered products and biological systems, ESA’s Advanced Concepts Team has already analysed some bio-inspired